Halftone diaphragm control



Nov. 29, 1949 R. P. NEwlcK HALFTONE DIAPHRAGM CONTROL Original FiledFeb. 25, 1942 3 Sheets-Sheet l Nov. 29, 1949 R. P. NEwlcK 2,489,804

HALFTONE DIAPHRAGM CONTROL Original Filed Feb. 23, 1942 3 Sheets-Sheet 2MMM Nov. 29, 1949 R P, NEMCK 2,489,804

HALFTONE DIAPHRAGM CONTROL Original Filed Feb. 23, 1942 3 Sheets-Sheet 3E111/undo@ mbox/144g Patented Nov. 29, 1949 HALFTONE DIAPHRAGM CONTROLRichard PL Newick, deceased, late of Rutherford, N. J., by Evelyn C.Newick, executrix, Grants Pass, Oreg.

substituted for application Serial No. 432,072

February 23, 1942. This application May 21, 1946, Serial No. 671,299

3 Claims.

This. application is a substitute for abandoned application, SerialNo.432,072, filed February 23, 1942.

The invention relates to apparatus for controlling the time andcharacter oi exposure in photographic processes, and more. specificallyisv designed to control the proportion of total eX- posure given at eachof certain selected lens apertures. The starting and stopping apertureof the lens are the only ones selected for size; all other changeautomatically at variable. speeds as the control operates.

The particular application of theinvention lies in the field ofphotochemical reproduction, and particularly to the half-tone processesin which an image made up of dots of various sizes is produced by meansof exposure of a sensitive mate,- rial under a half-tone screen. The dotimage is produced due to the exposure gradient in. the shadow of theelements of the screen, and since the sharpness and size of thisshadowis dependent on the lens opening, as Well as on screen distance andother factors, variation in the character of the dot image, and contrastof the reproduction may be effected by control of the lens aperture withits length of exposure. (In the past this control has been made by theoperator giving excessive exposures, having set the lens manually torespective apertures for each exposure. This requires the full attentionand time of an experienced operator to operate a single process camera.)By the use of the instant invention, however, the operator may attend toother duties during the time of actual exposure, because the controldevice to be described turns the illumination on at the beginning ofexposure, moves the lens diaphragm so that the proper proportion ofexposure is given at different sizes of lens opening, gives a finaladjustable exposure at the smallest lens opening selected, and turns offthe illumination to terminate the exposure and stops itself.

It should be understood that in this. specification, exposure refers notmerely to the time that a subject is being imaged on the sensitizedphotographic plate, but includes a measure of light action determined bythe size of aperture, and intensity of light reflected from the subjectand focused upon the plate by the lens.

It is an object of the invention to provide a device which will causepredetermined exposures to be made, and whichv will simultaneously varythe aperture of the lens over a preselected range oi diameter of theopening.

It is a further object to provide such a device 2 which is ruggedly yetsimply constructed, not liable to breakdowns, and which may be set intooperation by a relatively unskilled person.

An aim of the invention is to coordinate the desired range oi lensopenings with the degree of enlargement or reduction of the particularcopy being photographed, so that after being properly set and lightingadjusted for one scale of copying, such as equal size, the proper timeof exposure and series of apertures for another scale of copy may beselected by merely setting the pointer to such scale marking on a dial.

An additional feature of the invention is that it may be used withmanual control if desired, and will then indicate the proper lensopening and time of exposure required at that lens setting if a seriesof exposures at different apertures should be required rather than atthe continuously varying series of apertures which the device gives innormal operation.

An object attained by the invention is that of permitting a series ofexposures at continuously varying apertures followed by an exposure ofpreselected duration at a fixed aperture.

A further aim is to provide such a timing device in which the totalperiod of exposure may be varied while maintaining the selectedproportion of exposure at each aperture.

An additional attainment is the provision of means in such a devicewhereby the proportion of l total exposure made at any portion of therange of aperture used may be readily preselected.

Additional features, objects, and advantages of the invention reside inthe novel features, arrangements and combinations or parts as aredescribed in the accompanying specification of a preferred form of theinvention and shown in the accompanying drawings, wherein Figure l is afront elevation of an embodiment ofthe device in operative relation to aprocess camera objective and aperture diaphragm control.

Figure 2 is a side elevation thereof with parts in section.

Figure 3 is a rear elevation of the control device.

Figure 4 is a horizontal cross section thereof.

Figure 5 is a fragmentary top plan thereof.

Figure 6 is a schematic wiring cf the electrical circuits controlled bythe device.

Figure 7 is a fragmentary view similar to ure 1 illustrating a cableconnection with the c phragm lever.

There is illustrated a control device 25 adapted to operate inconjunction with photoznechanical process equipment 2l which comprisesan cbjective lens and mounting 23 which includes a variable aperture,illustrated as an iris diaphragm 24 operable by the rotatable ring 25and pointer arm 25'. Associated therewith is a scale I9 of conventionalj numbers and a scale I8 marked in degrees of enlargement, to be furtherdescribed. The ring 25 has also a radial pointer I8 associated with thescale I8.

The control device 26 is housed in a casing which includes a base 26which may be provided with a mounting flange 21, two end walls 28, afront panel 29, and a top 3|.

Mounted upon the front panel inside of a gear train 33 the terminal gear34 of which is meshed with the gear 35 fixed upon a clutch member 36.The terminal gear 34 of the train is made of sucient thickness so thatthe gear 35 may slide longitudinally thereon incident to operation ofthe clutch member 36.

At a central position on the front panel 29 a bushing 31 is secured;slidably and rotatablyl mounted therein is a hollow shaft or sleeve 38which extends outside the front wall 29 and has iixed thereon anoperating disc 39 adapted to be grasped by the fingers for pulling theshaft 38 longitudinally and for `rotating it. At the opposite end of theshaft 38 is mounted the clutch member 36 and associated gear 35 beforereferred to, which are freely rotatable on the shaft 38, and which areretained thereupon byv a ange 4U on the end of the shaft outwardly ofthe clutch member 36. Urging the clutch member 36 longitudinally towardthe flange 40 is a protractile helical spring 4I which is wound aroundthe shaft and confined between the member 36 and the inner end of thebushing 31. Suitable Washers or other anti-friction means may beprovided between the rotatable member 36 and the spring 38 to reducerestraining torques. The bushing 31 is formed with a radial slot 42extending around a portion of its circumference, and a longitudinal slot43 extending from the central part of slot 42 inwardly in the directionof spring 4I but stopping short of the end of bushing 31. Engagedalternatively in the slots 42 and 43 is a pin 44 which is fixed in theclutch operating hollow shaft or sleeve 38. It may be seen that the pin44 is urged to a seat at the end of the slot 43, but that when the disc39 and sleeve 38 are pulled forward when releasing the clutch, the pin44 will be carried to the slot 42 therein, on rotation of the shaft 33,it will be engaged and restrain shaft 38 against longitudinal returnmovement with respect to the bushing 31 when the disc 39 is released,thus holding the clutch out of engagement.

Journalled in the hollow shaft 38 and extending through the rear wall 30where it is received by a suitable bearing and securing means 45, is anaxle 45. Upon the forward end of the axle 46 is xed an operating knob 41and pointer 48 which extends radially beyond the disc 39 and may be setto any position of a dial 49 marked upon the front panel 29. Fixed uponthe axle 46 and spaced a suitable distance from the rear wall 39 is aface cam disc 59, which is formed with a clutch element I aligned, andadapted to engage, with the clutch element 36 before mentioned. rllheface of the cam disc 5l] which is presented to the rear wall is formedwith a spiral cam which is illustrated as a channel 52, but which may bea rib, if desired, in other constructions.

The cam 52 as shown in Figure 3, is not a simple spiral cam in which theradial movement of the follower due to certain angular rotation of thecam plate would be the same at whatever portion of the cam it might beengaged. As shown it is preferably made in the form of an expotentialspiral, the rate of radial movement relative to angular rotationbecoming less as the follower approaches the axis of rotation of the cam50.

Engaged in the cam channel 52 is a follower pin 53 carried by a slidebar 54 which is radial to the axle 46 and is carried in ways 55' whichare fixed upon the rear wall 30. Rotation of the face cam 59 will thuscause radial motion of the slide 54. It may be seen that a revolution ofthe cam will move the slide 54 radially the radial distance betweensuccessive turns of the spiralwhich is greater at the outer portions ofthe spiral than at the inner convolutions. Thus, a certain time ofexposure established by the number of revolutions which the cam maymake, may be accompanied by a variety of distances of travel of theradial slide, and, as will be further set forth, permits selection ofthe maximum and minimum lens openings regardless of the duration ofexposure. The slide 54 is extended upwardly a suitable distance abovethe top 3i of the case and carries an arm or lever 55 upon a pivot pin56, the arm 55 being extended downwardly and laterally or" the case, andcarrying upon its lower end a roller or spool 51 revolubly held in a pin58. The arm 55 is provided with several holes 59 spaced longitudinallythereof and adapted to receive the removable pin 56, whereby the lengthof the lever arm between the slide 54 and the roller 51 may be variedthrough choice of the pivot hole 59.

A lens aperture operating cable 69 is attached to the roller spool 51and is wrapped about it in a clockwise direction, leaving the spool atthe side adjacent the slide 54 and being carried up and hooked in one ofa series of longitudinally spaced holes 6I in the pointer arm 25' of thediaphragm operating ring 25. The spool 51 is frictionally held againstrotation to such degree that upon vertical travel of the slide 54 thelens aperture diaphragm 24 will be actuated, but the length of cable maybe varied by manual rotation of the spool 51 to take up the slack in thecable at any position of the slide 54 or the diaphragm 24.

The arm 55 is yieldably maintained in a down-I ward position by aretractile spring 65 attached to an offset anchorage 66 on the arm 55,and engaged at its other end upon an anchorage 61 at a lower corner ofthe back wall 39. The spring 65 extending across the casing and pullingthe arm 55 in toward the slide 54. Movement of the arm 55 toward theslide 54 is limited by a stop screw 62 engaged through a bracket 68 onthe slide, which also serves as a mounting for a vertical downwardlyprojecting adjustable contact operating pin or screw 69 and associatedlock 1U, to be further referred to.

In the normal vertical path of travel of the roller 51 an inclined-planestop 1I is mounted upon the top plate 3l, being carried in ways 12whereby it may be adjusted to and from the slide 54 and retained inadjusted position by a set screw 13. It will be seen that travel of theslide 54 downwardly will effect movement of the iris diaphragm 23 untilthe roller 51 encounters the inclined stop 1I. The arm 55 and roller 51will be moved sidewardly and slightly upward by rolling up the inclinedplane. Stoppage of downward movement of the extremity of the arm 55discontinues the pull4 of the cable 65, on the arm 25' and the diaphragmremains at xed aperture during a further exposure as a result, and nofurther movement of the diaphragm will result from continued downwardtravel of the slide 54. Adjustment of the stop 1| determines thebeginning of the stopping of movement of the diaphragm arm 25.

Fixedl on the under side of the top plate 6| is a switch assembly 14,which includes normally closed contacts and 16. The lower contact 16 iscarried on a spring leaf 11 which is extended into the path of travel ofthe operating pin 89 carried upon the slide 54, and carries a push block18 adapted to be engaged by the pin 69 as the slide 54 moves downwardly,thus separating the contacts 15 and 16. The position of the pin 69 maybe adjusted longitudinally of the slide 54 as it is threadedly engagedin the mounting B8, and it may be secured in adjusted position bytightening the lock screw 10.

The electrical circuits controlled by the device and the accessoryswitches and controls are illustrated in Figure 6. A power supply line80 is connected through a master two-pole fused switch 8| to a magneticswitch 82, which will be caused to make the circuit between the supply8| and lighting equipment 83, or other exposure defining means, when theexposure is begun, and to automatically break said circuit at the end ofthe exposure. The drive motor 32 is connected in parallel with thelighting equipment 83 through a two-pole fused switch 84, whereby themotor which ordinarily operates simultaneously with the lights 83 may bediscontinued if manual control be desired. A rheostat 85 is connected inseries with motor 32 so that its speed may be varied, if desired, whichwill result in a longer or shorter total exposure while maintainingconstant the percentage of said exposure made at each successivediaphragm opening. An alternative to the use of the rheostat for thispurpose would be to provide changeable gears in the drive 33.

The magnetic switch 82 is actuated by a solenoid-holding coil 86 andarmature 81 which includes an auxiliary contact 88 upon one pole of theswitch.

Means for controlling actuation of the switch 82 through energizing ofsolenoid coil 86 include two manual operating stations 89 and 98, eachof which includes a starting switch 9|, of a pushbutton type, normallyopen, and a stop switch 92 normally closed; and the switch 14 operatedby the control device 20. One terminal 93 of the solenoid coil 86 isconnected to the opposite side of the supply line from the contact 88,at the output of switch 8|. The other terminal 94 of the coil 86 isconnected in series with the start switch 9| at station 89, to theopposite line at the output of switch 8|. The terminal 94 isadditionally connected in series with the stop switch 92 at station 89and start switch 9|, normally open circuit, at station 98 to said outputline of switch 8|. It will be seen that operation of either switch 9| toclose the circuit will result in the coil being energized by powersupply from switch 8|, closing the contacts associated with the armature81, and placing lights 83 and control unit 28 in operation. In order tohold the switch 82 in closed position during the exposure after releaseof push-button switch 9|, the terminal 94 of the coil 86 is additionallyplaced in series with the two stop switches 92, the switch 14 of thecontrol unit 20'and the auxiliary contactl 88 of the switch 82 thusbeing placed in series with power supply by this circuit while themagnetic switch is closed. However, breaking this latter circuit ateither stop switch 92 or the control; switch 14 will de-energize thesolenoid 8B and break the circuit to the lighting equipment 83 andcontrol device 20.

The dial 49 is graduated to read in terms of the scale of the copy; inthe present case thev digits thereon represent tenths of reduction.Setting the pointer 48 to the corresponding dial position when making acopy of any degree of reduction has the eirect of selecting total timeof exposure and also of adjusting the maximum diaphragm opening used, toresult in a properly exposed negative of the best dot image formation.

In operation of the device various modifications of adjustment may bemade to alter theV character` of the image in the low dark portion ofthe image, or in the high light areas. Consequently, an individualrequirement for a reproduction may be met, and an identical eiectreproduced on a similar copy in the future; or a good standardadjustment for a run of work may be precisely made, and no furtheradjustments made during a run of similar copy, whether reproduction bemade at the same scale or at various degrees of reduction, the pointer48 being merely set to the proper point on the dial, or if enlargementpointer 8 is used.

When initially placed in operation, the intensity of lighting may beexperimentally adjusted at a one to one scale of copy so that with thepointer set to SS, (meaning same size) on the dial 49 at the start ofthe exposure, a proper range of densities will result in the finished.negative. Maximum and minimum sizes of lens opening may be selectedappropriate to the focal length used and the distance of the screen fromthe sensitized negative surface. Selection of maximum lens opening ismade with the slide 54 set to its highest point of travel, when set atSS in this instance, by setting the lens aperture lever 25 as desiredand taking up the slack in the cable 60 by means of the knob 62. Minimumsize of aperture may be elected in several ways, preferably by turningthe cam manually through that time of exposure to be given at varyingdiaphragm openings, which movement should cause the lens to be closeddown to that aperture at which the fixed aperture exposure is to begiven. The inclined stop 1| is now advanced to contact the roller 51, sothat further downward movement of the slide 54 will cause the roller toride up thereon, thus preventing further downward motion of the cable orfurther closing of the diaphragm. The cam 58 is now rotated through thetime of exposure which is to be given as a nal exposure, and the pin 69is adjusted to break the circuit at the switch 14, which willde-energize the magnetic switch 89, terminate exposure and stop thecontrol.

When actual exposure is to be made, the cam 58 will be driven by themotor 32 causing these lens settings and exposure times to be accuratelycoordinated and timed. Should the travel of the slide 54 in the requiredtime not be precisely of the extent to effect desired movement of thediaphragm ring 25,y the follower pin 53 may be engaged at a differentportion of the spiral cam 52 by manually turning the shaft 46 (afterdisengaging the clutch 35), lowering the slide 54 if a lesser amount oftravel is desired in a certain time, or raising it if a greater travelis desired".

The knob 41 maybeloosened on the shaft 46 and the pointer 48 set to theSS or other degree of reproduction being used, which will Zero thecontrol for the camera lens being used. Additionally, the cable Si) maybe reeved through one or another of the holes el in the diaphragmoperating lever and pointer 25 to increase or decrease the radius of itsattainment, so that the available movement of the cable will eiiectmotion of the diaphragm between the desired maximum and minimumpositions. This may be done as a nal adjustment at any time as may berequired by the'character of the particular copy.

Having been adjusted for proper reproduction at one scale of copying,similar copy may be photographed at any other degree of reduction andthe proper series of lens openings and exposures automatically given,merely by setting the pointer 48 to the corresponding position on thedial 49. This pointer is rotated in a counter-clockwise direction,raising the slide 54. When it is desired to give a long exposure for thedetail of a copy, use the incline stop il, which to stop movement of thediaphragm for a given amount of time while the lights are on.

Control of the character of dot image on the various tonal portions ofthe reproduction may be made by selecting the portion of total exposuremade at the larger diaphragm openings relative to that given at thesmaller openings, particularly the relative length of the last part ofthe exposure, which is made at the smallest lens diameter selected. Ifthe slide 55 is operated by the outermost portion of the cam 52 it willbe seen that a rather sudden closing action of the diaphragm withrespect to time will result, and little exposure period given at thelarger lens opening. The inclined stop 'H may be adjusted so that thesize of the detail dots can be made any size desired. The smaller thelens opening with the correct exposure the smaller the dot. The highlights of the negative are controlled by giving more or less exposurewith the large lens opening. Starting lower a more high light adjustmentis made with cable to lens pointer.

Should manual operation and use of one, two or three stop systems bedesired, the lens opening may be set properly according to the scale ofthe copy by disengaging the clutch with the disc 39 and turning thepointer 58. On opening the switch 34, disconnecting the motor 32, thelights may be operated from either of the stations 89 or 95. The lightsremaining on after pushing a start button 9 l, until one of the stopbuttons 92 is operated.

The lever 25', the arm 55, the spool 5l, stop block ll and cable B maybe termed a lost motion connection between the diaphragm and thediaphragm operating means, since motion of the operating membercontinues and the lever 25 stops although the operative connection ofthe parts through the cable continues.

On the switch case 14 there is shown a load leaf spring 93, the blade ofwhich is extended in the path of the screw 55 of the slide 54, andclosely over the push pin i8 of the switch blade 11. It will be seenthat a slight depression of the spring 93 will open the switch l5 andstop the exposures. Operation of this spring for this purpose willtherefore be eected by the screw 69 when the cam has moved the slide 55to the desired lower limit. The timing of the circuit breaking functionof the machine may be effected by loosening the lock screw and rotatingthe screw 69 so as to move it up or down on the slide 8. 54 todelay'or'advance the opening of the switch 14. The spring 93 may bemanually operated through the top 3| of the case, if desired, and soconstitute a manual light extinguishing means in addition to the stopswitches above described. It functions to eliminate possibility ofoperation of the switch 'il by the slide before loose connections orother play have been compensated for and to effect breaking of thecircuit only when the cam 59 positively presses the pin 53 downwardly tothe desired limit.

It will be appreciated that by the construction presented, afteradjustment of the pointer on the dial it is only necessary to operatethe starting switch, and thereafter all necessary functions which wouldordinarily involve calculations and judgment are automatically performedby my timing device, the exposure begun, the necessary setting of thediaphragm effected at the proper times, and the exposures terminatedafter the proper period with the larger opening.

While there has been disclosed with great particularity a speciiicconstruction of apparatus embodying the invention and capable ofperforming the stated functions, it will nevertheless be understood thatthis is simply the best form of the device thus far constructed, and ispurely exemplary, various changes in the construction, arrangement,combination of parts, substitution of materials, substitution ofmechanical equivalents and modiiications of design, being possiblewithout departing from the spirit of the invention except as moreparticularly limited by the appended claims.

In Figure 7 there is illustrated a means for connecting the cable 5d tothe diaphragm, adapted to improve the nicety of adjustment of theoperation of the diaphragm. in this instance, the lower operating deviceincluding the slide 54 and arm 55 is as before described and the cable6B is attached thereto in the same manner. In place of the single arm25', however, a much longer arm lll is provided on the operating ring 25of the diaphragm, but it may be in the same relative radial location. Itis preferably rectangular in cross section and is provided with amultiplicity of longitudinally spaced apertures or indentations i8!exposed at the front side, and engaged on this arm there is aclose-iitting slide |52 having a set screw 453 engaged through its frontside for alternative engagement in the apertures or indentations l5! tohold the slide in adjusted positions on the arm. The arm lili! may stillserve as a pointer on a scale i9' similar to the one I9 beforementioned, calibrated in focal ratio numbers arranged at a greaterradius than in the rst instance. Likewise, from the opposite side of thediaphragm ring a shorter arm ES as before operatively associated with ascale i8 calibrated in numbers indicating respective ratios ofenlargement or reduction, or SS (same size).

The slide HG2 is formed with a downward extension IE5 in the shape of anarm curved toward the left in its outer part so that when the slide isat its left hand limit of sliding movement the arm will be approximatelyconcentric with the diaphragm ring 25. Extending upwardly from the slidethere is an arm E55 which in addition to having a portion curved towardthe left at its upper part also has a part curved toward the right, thisbeing attained by forming the arm as a flat plate broadened toward itsupper part suitably to aiord left and right edges ll and IUS of thedesired curvature.

Throughout the length of the arm |05 there are longitudinally spacedapertures |00, arranged in a curved series, while adjacent each of thecurved edges |01 and |08 there are respective series of apertures I Iand I I I. The cable 50 has its anchor hook 60 engaged in one of theapertures of the slide extensions |05 and |06 alternatively. It will beseen that by connecting the cable to apertures toward the outer parts ofthe extensions |05 and |06 the :motion produced in the arm |00 byvertical movement of the slide will have varying angular components ofmotion in proportion to given units of vertical motion of the slide,which may be availed of for operation of the diaphragm. Also, a greaterrefinement of adjustment of the cable connection at points radiallyspaced with respect to a projection of the cable across the arm |00 maybe secured while still using anchorage apertures of substantial size andwell spaced, so that manual change of the connection of the cable to thearm may be most easily eiected. This permits finer gradations of thedegree of movement of the diaphragm and sizes of aperture in relation toa given timing of the exposure and change of aperture.

The invention claimed is:

1. In a half tone exposure device, a variable aperture type diaphragm, aprimary operating member, and operative connections between the latterand the diaphragm including a lost motion connection operative over apart of the movement only of the operating member, whereby the diaphragmremains at a fixed aperture for a time, and including an adjustablemember operative to cause initiation of the lost motion relation betweendiaphragm and primary operating member at a predetermined part ofmovement of the device, variable at will.

2. In an exposure device of the character described, an iris diaphramhaving an operating lever, an operating member movable in a path at asubstantial angle to the mean position of the operating lever, means tomove the operatlng member from an initial position to a predeterminedlimit of movement, an arm pivoted on said operating member, means foryieldably maintaining the arm in a downward position, a take-up reel onthe extremity of the arm, a cable anchored at one end on said operatinglever and wound at its other end on said reel, means to hold said reelagainst unreeling, a surface element in the path of said reel beinginclined and adjustable toward and away from the incident path of thereel under its movement initially with the operating member, the surfaceelement being disposed at such angle to said path that the reel willroll thereon laterally, moving said arm so that the reel and arm willswing with elements of motion in the direction of said operating lever.

3. The structure of claim 2 wherein said arm has a plurality oflongitudinally spaced apertures for alternative pivoting of the armtherein, said arm being extended laterally of the path of the operatingmember, said surface element being a slidable member adjustable towardand away from the said path of the operating member in the plane of thepath of the pivotal movement of said arm, means to hold the surfaceelement releasably at adjusted positions, and friction means to hold thereel against rotation except by said surface element and predeterminedforce.

EVELYN C. NEWICK. Eecutri of the last Will and Testament of Richard P.Newick, Deceased.

REFERENCES CITED UNITED STATES PATENTS Name Date Newick Mar. 7, 1939Number

